JP2009151861A - Perpendicular recording head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a perpendicular recording head suppressing a magnetic field leaked to an adjacent recording track during recording to increase a density in a track width direction. <P>SOLUTION: The perpendicular recording head constituted of a main magnetic pole and an auxiliary magnetic pole includes a leading side shield arranged to separate a magnetic body from the main magnetic pole by a certain distance and retreat the height position of the magnetic body from the storage medium facing surface of the main magnetic pole in a track width direction from the leading side of the main magnetic pole when viewed from the storage medium facing surface. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a thin-film magnetic head used for recording / reproduction of a magnetic disk or the like and a magnetic disk apparatus equipped with the same.

  In a magnetic disk device, data on a storage medium is read and written by a magnetic head, and in order to increase the recording capacity per unit area of the storage medium, it is necessary to improve both the track width and the bit length density. . However, in the current in-plane recording method, when the bit length to be recorded becomes short, there arises a problem that the surface recording density cannot be increased due to thermal fluctuation of the storage medium. As a method for solving this, a perpendicular recording system in which magnetization is performed in a direction perpendicular to the medium is being put into practical use for further increase in density.

  On the other hand, in the magnetic head, a giant magnetoresistive head (GMR head), a tunnel magnetoresistive head (TMR head) having a larger reproduction output than the giant magnetoresistive head, and the like are used for reproduction. In the recording process of perpendicular recording, the perpendicular storage medium is divided into two layers, a soft magnetic underlayer (SUL) is provided in the lower layer, and a single magnetic pole head having a main magnetic pole and an auxiliary magnetic pole is used as a recording head for recording. ing. As described above, since the SUL is provided on the vertical storage medium side, the perpendicular recording method has a high effective head writing capability and can write on a recording layer having a relatively large coercive force exceeding 5 kOe (Oersted). .

  However, as the recording density increases, the recorded track width decreases, and the magnetic material used for the main pole is also limited by the saturation magnetic flux density. The magnitude of the magnetic field is also limited. Therefore, even if the magnetomotive force is increased in order to obtain a large generated magnetic field, the magnetic field required for writing does not change due to magnetic material limitations, and only unnecessary (leakage) magnetic flux increases, resulting in higher density. It is difficult. In particular, in a magnetic disk apparatus, the magnetic head may perform recording at a skew angle of 15 to 20 degrees at the maximum, and erasure of adjacent tracks due to the leading edge of the main pole protruding (writing spread) becomes a problem. .

  FIG. 8 shows the state of the leakage magnetic field in the main magnetic pole of the perpendicular recording head. (A) shows the magnetic field leakage when the main magnetic pole is tilted, and (b) shows the magnetic field leakage from the edge of the main magnetic pole. ing. FIG. 8 shows a general conventional form of a side shield in which magnetic bodies are arranged on both sides of the main magnetic pole 101 in the track width direction. In the case of the conventional embodiment, since the magnitude of the magnetic flux from the leading edge of the main pole 101 is strong, there arises a problem that information is rewritten when a narrow track and a large skew angle (θ) are provided, resulting in high recording density. It becomes difficult.

  Several techniques have been proposed with the aim of preventing such spread. For example, in Patent Document 1, as shown in the overview diagram of the front end of the main pole of the conventional perpendicular recording head in FIG. 9, it is viewed from the medium facing surface for the purpose of suppressing the magnetic field expansion in the track width direction (FIG. 9B )), A perpendicular recording head that includes a trailing shield 103 and a side shield 102 of the main magnetic pole 101 and whose leading shield and side shield are magnetically connected has been proposed.

  Also, Patent Document 2 proposes a perpendicular recording head having a plurality of stripe-shaped shields on the periphery so as to surround the main pole on the medium facing surface.

However, in any case, even if it can be absorbed to suppress the spread of writing from the main magnetic pole, the shape of the shield is exposed on the medium facing surface side. Have a problem that occurs.
JP 2005-122887 A JP 2007-52904 A

  In order to solve the above problem, in the present invention, perpendicular recording having a magnetic body arranged at a position retreated from the medium facing surface at a certain distance from the main pole from the main pole leading side to the track width direction. Provide the head.

  According to a first aspect of the present invention, in a perpendicular recording head including a main magnetic pole and an auxiliary magnetic pole and having a trailing shield on the main magnetic pole, as viewed from the storage medium facing surface, the leading side of the main magnetic pole extends in the track width direction. The present invention relates to a perpendicular recording head characterized in that the magnetic material is arranged at a certain distance from the main magnetic pole, and the height position of the magnetic material is set back from the medium facing surface of the main magnetic pole.

  That is, according to the first invention, when viewed from the storage medium facing surface, the magnetic material is separated from the main pole by a certain distance from the leading side of the main pole to the track width direction, and the height from the storage medium facing surface. Only the extra magnetic flux that is going to be written on the main pole can be absorbed by the magnetic material that has been moved backward, and even if the absorbed magnetic flux is discharged to the medium side, Since it is arranged, only the magnetic flux whose magnetic flux intensity is weakened in proportion to the square of the distance is applied to the medium side, so that erasure caused by the shield magnetic domain can be suppressed.

  The second invention relates to the perpendicular recording head according to the first invention, characterized in that the magnetic body disposed so as to recede from the surface facing the storage medium has a U shape surrounding the side surface of the main magnetic pole. .

  That is, according to the second aspect of the present invention, the magnetic field placed backward from the storage medium facing surface is U-shaped and the main magnetic pole is surrounded so that the leakage magnetic field to the adjacent track is suppressed to the maximum. Therefore, at the time of writing, only the magnetic flux effective for recording can be taken out on the storage medium.

  According to a third aspect of the present invention, in the first or second aspect, the magnetic body disposed so as to be retracted from the surface facing the storage medium is provided with a gap having a predetermined interval between the magnetic shield and the trailing shield. The present invention relates to a perpendicular recording head described in the invention.

  That is, according to the third aspect of the present invention, the gap between the magnetic body and the trailing shield disposed backward from the storage medium facing surface is provided with a constant gap, thereby minimizing the decrease in the write magnetic field. It is possible to efficiently absorb only the extra magnetic flux that is about to spread from the tip of the magnetic pole.

  According to a fourth aspect of the invention, the magnetic body disposed so as to be retracted from the storage medium facing surface is in a state of being magnetically floated or connected to an auxiliary magnetic pole on the leading side of the main magnetic pole. The present invention relates to the perpendicular recording head according to any one of the first to third inventions.

  That is, according to the fourth aspect of the invention, the magnetic material disposed so as to be retracted from the surface facing the storage medium is configured to be in a state of being magnetically floated or connected to the auxiliary magnetic pole on the leading side of the main magnetic pole. The leakage magnetic field can be suppressed, and writing to the storage medium can be performed efficiently.

  According to a fifth aspect of the present invention, the magnetic body disposed so as to recede from the surface facing the storage medium is composed of a soft magnetic body, and the soft magnetic body is equal to or less than a saturation magnetic flux density of the main magnetic pole. The perpendicular recording head according to any one of the first to fourth inventions.

  That is, according to the fifth aspect of the present invention, the magnetic material is composed of a soft magnetic material, and the saturation magnetic flux density is equal to or less than the saturation magnetic flux density of the main magnetic pole, whereby the magnetic flux flows from the main magnetic pole to the magnetic medium. However, there is no resistance, and the magnetic circuit becomes smooth and less loss is formed.

  According to a sixth aspect of the present invention, in any one of the first to fifth aspects of the present invention, the main magnetic pole has a drawing structure in the film thickness direction on the leading side and the trailing side of the main magnetic pole. The present invention relates to a perpendicular recording head.

  That is, according to the sixth aspect of the invention, the magnetic material is arranged by separating the main magnetic pole from the main magnetic pole leading side over the track width direction by a certain distance from the main magnetic pole and retracting from the storage medium facing surface. It is possible to adopt a structure in which the main magnetic pole is narrowed in the film thickness direction from both sides of the leading and trailing, and the magnetic field required for writing can be greatly improved by this narrowing structure of the main magnetic pole.

  As described above, the present invention produces the following effects.

  In a perpendicular recording head composed of a main magnetic pole and an auxiliary magnetic pole, the magnetic material is separated from the main magnetic pole by a certain distance from the leading side of the main magnetic pole in the track width direction when viewed from the surface facing the storage medium, and the magnetic By adopting a configuration in which the height position of the body is set back from the surface facing the storage medium of the main magnetic pole, the spread of writing in the track width direction at the time of writing can be suppressed without causing a decrease in the magnetic field required for writing. it can.

  Even when the skew angle when the magnetic head is incorporated in the magnetic disk device is taken into account, the magnetic flux on the leading magnetic pole leading side can suppress the leakage magnetic flux from the leading edge portion, thereby suppressing the spread of writing.

  In addition, the magnetic material extending from the main magnetic pole leading side to both sides is disposed with the magnetic material height position retracted from the surface facing the storage medium of the main magnetic pole, thereby minimizing the decrease in the write magnetic field, Only the extra magnetic flux that is going to spread from the tip can be efficiently absorbed. Although it is conceivable that the absorbed magnetic flux is discharged to the storage medium side, since the magnetic material is disposed at a position retracted from the storage medium facing surface, the magnetic field strength becomes weaker in proportion to the square of the distance, In addition, since it is weakened to a negligible level with respect to the magnetization state of the recording bits of the storage medium, no erasure caused by the shield magnetic domain occurs.

  Therefore, by adopting the form of the present invention, it is possible to improve the erase problem with respect to the adjacent track without deteriorating the writing performance, and a great increase in recording density can be expected. Furthermore, by separating the main pole from the main pole leading side over the track width direction by a certain distance from the main pole and retreating from the storage medium facing surface, the magnetic material is arranged from both sides of the main pole leading and trailing, It is also possible to adopt a structure in which the main magnetic pole is narrowed in the film thickness direction, the magnetic field required for writing can be greatly improved, and a more practical perpendicular recording head can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows the basic configuration of a magnetic disk drive equipped with a perpendicular recording head according to an embodiment of the present invention. This embodiment shows a schematic configuration of a magnetic disk device to which a perpendicular recording head is applied, and shows a relationship between a storage medium and a magnetic head.

  The slider 2 is fixed to the tip of the suspension arm 3 supported by the rotary actuator 4, and although not shown, the slider 2 is fixed to the tip of the suspension arm 3 with a support called a gimbal. Information is recorded on and reproduced from the storage medium 5 that rotates in the medium rotation direction R by the magnetic head element 1 provided at the end of 2. In the magnetic head element unit 1, the recording head is a perpendicular recording head in which a trailing shield is disposed on the main magnetic pole trailing side, and the reproducing head is a magnetoresistive element (GMR) or tunnel magnetoresistive. An effect element (TMR) is used.

  By rotating the rotary actuator 4, the magnetic head element 1 is moved to a different radial position on the storage medium 5, and the magnetic head element 1 can be positioned. At this time, concentric recording tracks 6 are formed on the storage medium 5. The recording density in the track width direction is determined by forming a plurality of concentric recording tracks 6 at a certain narrow interval.

  FIG. 2 is a schematic diagram showing the flow of magnetic flux between the recording head and the storage medium of the magnetic head in perpendicular recording.

  A recording head composed of a main magnetic pole 11, an auxiliary magnetic pole 12, a magnetic core 13, and a coil 16, and a recording medium composed of a recording layer 14 and a soft magnetic backing layer 15 are disposed to face each other.

  When a current is passed through the coil 16 of the recording head and excited, a perpendicular magnetic field is generated between the tip of the main magnetic pole 11 and the soft magnetic backing layer 15, whereby recording bits are recorded on the recording layer 14 of the storage medium.

  F in the figure indicates the flow of magnetic flux, and the magnetic flux that has flowed into the soft magnetic backing layer 15 returns to the auxiliary magnetic pole 13 to form one magnetic circuit. At that time, the recorded magnetization state is determined by the shape of the main magnetic pole 11 on the surface facing the storage medium. In particular, recording is performed by a large magnetic field on the downstream side of the storage medium in the medium traveling direction, that is, on the trailing edge of the main magnetic pole 11.

  FIG. 3 is a schematic view of the entire recording / reproducing integrated head according to the embodiment of the present invention. In this example, the entire configuration of a perpendicular recording head that controls recording is shown. (A) shows a plan view of the recording / reproducing integrated head viewed from the storage medium facing surface on the storage medium side, and (b) shows an A-A ′ cross section in (a). The magnetic head element 1 has a configuration in which the reproducing head and the recording head are integrated, and the storage medium facing surface is formed to face the recording layer 14 of the storage medium.

  The reproducing head is provided on the leading side of the magnetic head element 1 and includes a reproducing element 21 and a pair of magnetic shields 22 and 23. As the reproducing element 15, a magnetoresistive element (GMR) or a tunnel magnetoresistive element (TMR) having a property of changing an electric resistance in accordance with a magnetic field applied to the storage medium is applied, and a recording bit on the storage medium is applied. Is converted into an electric signal to read out information.

  On the other hand, the recording head is provided on the trailing side of the magnetic head element 1, and includes a main magnetic pole 11, auxiliary magnetic poles 12 and 17, a coil 16, a main magnetic pole trailing side shield 18, and a magnetic body 19 as a leading side shield. I have.

  As shown in FIG. 3A, the main magnetic pole 11 is formed perpendicular to the storage medium facing surface. As shown in (b), the main magnetic pole 11 has a tapered diaphragm structure whose width decreases toward the storage medium facing surface as viewed from the leading side. The reason why the main magnetic pole 11 has a tapered structure is as follows.

  According to the position in the radial direction of the storage medium, the angle formed by the magnetic head element 1 and the recording track 6, that is, the skew angle (θ) changes to various angles (changes in the range of ± 15 ° to 20 ° at maximum). Therefore, a large magnetic field is applied to the adjacent recording track 6 and the magnetic domain of the adjacent track is erased (see FIG. 8).

  In order to prevent the influence of such a skew angle, the shape protruding from the recording medium facing surface at the tip of the recording head is a trapezoidal shape in which the side on the leading side is smaller than the side on the trailing side. It is shaped like an inverted trapezoid when viewed from the leading side.

  FIG. 4 shows a configuration example of the perpendicular recording head according to the embodiment of the present invention. 4A is a cross-sectional view of perpendicular recording, FIG. 4B is a plan view seen from the surface facing the storage medium, and FIG. 4C is a cross-sectional view along B-B ′ of FIG.

  As shown in FIG. 4B, the perpendicular recording head includes a main magnetic pole 11 and a trailing shield 18 on the main magnetic pole trailing side, and the magnetic body 19 extends from the main magnetic pole leading side to the track width direction. 11 is separated from the magnetic pole 11 by a certain distance, and the height of the magnetic material is set so as to recede from the surface facing the storage medium of the main magnetic pole, and is separated from the trailing shield 18.

  The magnetic material 19 is arranged on both sides of the leading side of the main magnetic pole at a predetermined distance from the main magnetic pole 11 according to the track pitch, thereby extending the writing in the track width direction without causing a decrease in the magnetic field required for writing. Can be suppressed. Since the magnetic body 19 on the leading side of the main magnetic pole of the present invention suppresses the leakage magnetic field from the leading edge portion, it also serves as a countermeasure against leakage of magnetic flux due to the skew angle when the perpendicular recording head is incorporated into the magnetic disk.

  In the case of the conventional side shield type in which the magnetic material is arranged on both sides of the main magnetic pole track width direction as shown in FIG. 9, the magnetic field from the main magnetic pole leading edge is strong as shown in FIG. The problem of rewriting information when a track has a large skew angle is solved by the backward arrangement of the magnetic body 19 of the present invention.

  That is, a structure in which the magnetic body 19 arranged with a certain interval from the main magnetic pole leading side to the both sides is arranged with the height of the magnetic body 19 slightly retracted from the storage medium facing surface of the main magnetic pole 11 is arranged. As a result, it is possible to minimize the decrease in the write magnetic field and efficiently absorb only the extra magnetic flux that is intended to spread from the tip of the main pole.

  Although the magnetic flux sucked out may be discharged to the storage medium side, the magnetic body 19 is arranged at a position retracted from the surface facing the storage medium, so that the magnetic field strength is weakened in proportion to the square of the distance. As a result, there is a merit that the shield magnetic domain does not cause erase.

  Further, by adopting the form of the present invention, it is possible to improve the erase problem with respect to the adjacent track without deteriorating the writing performance, so that a significant increase in recording density can be expected. Further, when the magnetic material 19 is arranged at a certain distance from the main magnetic pole 11 from the main magnetic pole leading side to the track width direction and retracted from the surface facing the storage medium, the reading of the main magnetic pole 11 and It is possible to adopt a structure in which the main magnetic pole is narrowed in the film thickness direction from both sides of the trailing, and the magnetic field required for writing can be greatly improved.

  FIG. 5 shows an example of the arrangement and shape of the magnetic shield according to the embodiment of the present invention. FIG. 5 is a plan view seen from the storage medium facing surface side to reduce the influence of leakage magnetic flux in the inverted trapezoidal main magnetic pole 11, the U-shaped magnetic body 19, and the trailing shield 18. A suitable positional relationship is shown.

  Here, the distance between the upper part of the U-shaped side surface of the magnetic body 19 and the long side edge of the inverted trapezoidal shape of the main pole 19 is a, and the shorter side of the inverted trapezoidal shape of the U-shaped side part of the magnetic body 19 and the main pole 19 The distance from the edge is b, and the distance between the U-shaped upper surface of the magnetic body 19 and the lower part of the trailing shield 18 is d.

  (A) shows a case where a = b in which the distance between the main magnetic pole and the U-shaped side surface is constant, (B) shows a case where a> b where the distance increases in the upper part of the U-shaped side surface, and (C) shows In this example, the distance from the ring-side shield is dd ′ where the main magnetic pole is lifted by d ′.

  FIG. 6 shows an example of the main magnetic pole stop structure according to the embodiment of the present invention. This example shows a cross section similar to that of FIG. 4C, and a magnetic field is effectively applied to the storage medium by narrowing the main pole 11 in the film thickness direction from both the leading and trailing sides of the main pole 11. A preferred structural example is shown.

  FIG. 7 shows a simulation result in which the distance from the storage medium facing surface of the magnetic material arranged on the leading side is used as a parameter.

  In order to confirm the effect of the present invention, FIG. 7 shows a main magnetic pole leading side on a main magnetic pole 11 and a perpendicular recording head having a trailing side shield 18 on the main magnetic pole trailing side as viewed from the surface facing the storage medium. The result of simulating the magnetic body 19 arranged at a certain distance from the main magnetic pole 11 in accordance with the track pitch in the track width direction from the storage medium facing surface as a parameter is shown.

  The horizontal axis indicates the distance from the surface facing the storage medium of the magnetic body 19 arranged from the main magnetic pole leading side over the track width direction, and the vertical axis is adjacent to the recording magnetic field estimated by simulation as an index of the sharpness of the magnetic field distribution. This is shown as the ratio of the erase magnetic field. Further, MMF (Magnetomotive Force) = 0.2 AT (ampere turn) in the figure indicates the coil application condition.

  FIG. 7 shows that the ratio of the recording magnetic field and the adjacent erase magnetic field that improves the magnetic field distribution when the magnetic body 19 arranged over the track width direction from the leading side of the main pole is retracted by about 40 nm from the surface facing the storage medium is minimized. It shows that there is an optimal value.

  This means that if the leakage magnetic flux ejected from the portion where the main magnetic pole tip is physically smallest can be efficiently absorbed in order to write on the storage medium side, the magnetic field required for writing is reduced. This means that only the magnetic flux leaking to the adjacent track can be controlled. Furthermore, in the embodiment of the present invention in which the magnetic body 19 is arranged at a certain distance from the main pole 11 and back from the storage medium facing surface across the track width direction from the main pole leading side, the leading of the main pole 11 is arranged. It is also possible to adopt a structure in which the main magnetic pole is narrowed in the film thickness direction from both sides of the trailing, and the magnetic field required for writing can be improved by 30% or more compared to the structure in which no restriction is made.

  The embodiments described so far are only examples, and the present invention is not limited to these examples.

1 is a diagram showing a basic configuration of a magnetic disk device equipped with a perpendicular recording head according to an embodiment of the present invention. It is a schematic diagram showing the flow of the magnetic flux between the recording head / storage medium of the magnetic head in perpendicular recording. 1 is a schematic view of an entire recording / reproducing integrated head according to an embodiment of the present invention. 2 is a diagram illustrating a configuration example of a perpendicular recording head according to an embodiment of the present invention. FIG. It is a figure which shows the example of arrangement | positioning and shape of the magnetic body shield which becomes embodiment of this invention. It is a figure which shows the aperture_diaphragm | restriction structure example of the main pole which becomes embodiment of this invention. It is a figure which shows the simulation result which used the distance from the storage medium opposing surface of the magnetic body arrange | positioned at the reading side side as a parameter. It is a figure which shows the mode of the leakage magnetic field in a perpendicular recording head main pole. It is a general-view figure of the front-end | tip part of the conventional perpendicular recording head main pole.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Magnetic head element 2 Slider 3 Suspension arm 4 Rotary actuator 5 Storage medium 6 Recording track 7 Spindle motor 11 Main magnetic pole 12, 17 Auxiliary magnetic pole 13 Magnetic core 14 Recording layer 15 Soft magnetic backing layer 16 Coil 18 Trailing side shield 19 Magnetic body 21 Read element 22, 23 Magnetic shield F Flow of magnetic flux R Direction of medium rotation

Claims (6)

In a perpendicular recording head composed of a main magnetic pole and an auxiliary magnetic pole and having a trailing shield on the main magnetic pole,
When viewed from the storage medium facing surface, the magnetic material is separated from the main magnetic pole by a certain distance from the leading side of the main magnetic pole in the track width direction, and the height of the magnetic material is set higher than the medium facing surface of the main magnetic pole. A perpendicular recording head, wherein the perpendicular recording head is disposed backward.   2. The perpendicular recording head according to claim 1, wherein the magnetic body disposed so as to recede from the surface facing the storage medium has a U shape surrounding the side surface of the main magnetic pole.   3. The perpendicular recording head according to claim 1, wherein the magnetic body disposed so as to recede from the surface facing the storage medium is disposed with a gap of a predetermined interval between the shield and the trailing side shield. .   4. The magnetic material disposed so as to recede from the surface facing the storage medium is in a state of being magnetically floated or connected to an auxiliary magnetic pole on the leading side of the main magnetic pole. The perpendicular recording head according to any one of the above.   The magnetic material disposed so as to recede from the surface facing the storage medium is composed of a soft magnetic material, and the soft magnetic material is equal to or less than a saturation magnetic flux density of the main magnetic pole. 5. The perpendicular recording head according to any one of 1 to 4.   6. The perpendicular recording head according to claim 1, wherein the main magnetic pole has a diaphragm structure in a film thickness direction on a leading side and a trailing side of the main magnetic pole.

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